Data networks in accordance with IEEE 802.3, as published by the Institute of Electrical and Electronics Engineers, Inc., New York, and commonly known as Ethernet networks, are restricted to a data path length of about 100 meters between data terminal equipment (DTE) units, in the event that the data transfer medium is constituted of unshielded twisted wire pairs. Power over Ethernet (PoE), in accordance to IEEE 802.3af-2003 published by the Institute of Electrical and Electronics Engineers, Inc., New York, the entire contents of which is incorporated herein by reference, is delivered over a set of 2 twisted wire pairs, and is limited to delivering less than about 13 watts for consumption by a powered device (PD). Enhanced PoE, in accordance with IEEE 802.3at-2009 published by the Institute of Electrical and Electronics Engineers, Inc., New York, the entire contents of which is incorporated herein by reference, is delivered over a set of 2 twisted wire pairs, and allows for delivering in excess of 13 watts for consumption by the PD. In either case, both power and data are delivered over a single cable of twisted wire data pairs, and in order to ensure that data is delivered without excess distortion the distance between two data terminal equipments (DTEs) on a link is limited to a range of 100 meters.
The above mentioned IEEE 802.3af-2003 and IEEE 802.3at-2009 standards are restricted to delivering power over a single set of 2 twisted wire pairs. Various strategies to deliver power over all 4 twisted wire pairs have been disclosed in U.S. Pat. No. 7,492,059 issued Feb. 17, 2009 to Peker et al.; U.S. Pat. No. 7,299,368 issued Nov. 20, 2008 to Peker et al; and U.S. Pat. No. 7,460,889 issued Dec. 2, 2008 to Darshan et al, the entire contents of all of which are incorporated herein by reference.
U.S. Pat. No. 7,466,819 issued Dec. 16, 2008 to Lehr et al, teaches that a hub equipment, such as a switch, bridge or router, may receive power over the communication cabling, and forward some of the power to a DTE, thus enabling an extension of powering and data communication in excess of the aforementioned 100 meter limit. Commercially available devices implementing such technology are readily available, and are typically known as PoE extenders.
Unfortunately, commercially available PoE extenders are extremely limited, and do not take advantage of the ability to deliver power over all 4 pairs of wires. As a result, the 100 meter limit is only stretched by an additional 100 meters.